One of the presently known methods of performing isometric exercises consists in manually moving the limb to be treated, while performing thrusts or counter thrusts in order to force the muscles of the limb to work and thus help them return to their initial prior shape and quality. This method can give good results, however it nevertheless suffers from the major drawback of requiring action by a practitioner, e.g. a physiotherapist, whose professional qualifications are not essential for performing this work.
Devices have therefore been made which, to some extent, replace the practitioner, thereby releasing the practitioner for other tasks which are better adapted to professional competence.
The apparatus described in the document constituted by German patent application filed Oct. 4, 1980 and published under the number 3 037 619 was made for this purpose.
That apparatus comprises a carriage mounted on slideways, means for applying reaction forces to the carriage, e.g. a weight on which gravity may act, and a leg-holding trough pivotally mounted at one end about an axis perpendicular to the direction of carriage displacement. In theory, this device gives good results. However, as exercises are performed thereon, various parts constituting the apparatus rapidly take on slack unless they are of the very highest mechanical quality, and it can then happen that the trough does not move in a plane perpendicular to the axis of rotation of the patient's knee joint. As a result, when the patient exerts leg force, the trough may be deflected from said plane, thereby giving rise to twisting which is dangerous for the knee. Thus, while seeking to treat one trauma, it is possible to create others which are just as bad for the patient.
In order to avoid these drawbacks, apparatuses have been made using mechanical components of very high quality and great reliability. However, this technique causes the price of the apparatus to be so high as to make it inaccessible for many practitioners.
Apparatuses have also been made for mitigating the two above-mentioned drawbacks, for example apparatuses as described in published French patent applications numbers 2 085 118 and 2 454 798. These apparatuses are essentially constituted by a trough comprising two parts which are hinged to each other at respective ones of their ends, with their other ends being pivotally mounted either directly or indirectly to a rigid base. This design limits unwanted trough movement of the type mentioned above, but the cost price of the device is not much less since the trough now includes two elements, one for holding the lower leg and the other for holding the thigh, and also, since it requires a rigid base which is relatively long.
The object of the present invention is to provide an apparatus for therapeutic exercise which can be made using a small number of standard-quality components so as to ensure a low cost price, together with weight and bulk that are considerably less than those of prior art devices, while still providing the same high quality of care.